Silicone rubber is a special synthetic rubber containing silicon atoms. Its molecular structure is:

6000 to 7000 silicone units contained long chain is divided into two main categories of heating vulcanized silicone rubber and room temperature vulcanized silicone rubber (RTV vulcanized silicone rubber). For example, a silicone rubber waterproof coating disclosed in CN201510082164.8 uses silicone rubber as main material, which contains 20 to 30 parts of silicone rubber emulsion, 5 to 10 parts of VAE emulsion, 20 to 30 parts of deionized water, 1 to 5 parts of nano-SiO2, 20 to 30 parts of white carbon, 1 to 2 parts of turpentine, 0.1 to 0.5 parts of sodium dodecyl benzene sulfonate (SDBS), 2 to 6 parts of hollow microspheres, 0.1 to 1 parts of leveling agent RM-2020, 1 to 2 parts of coupling agent, 1 to 2 parts of defoamers, 1 to 2 parts of dispersant, 0.1 to 0.5 parts of fungicide, 1 to 5 parts of bentonite. It is water-resistant and not susceptible to environment aging, and has a good mould proof effect. But this coating cannot be particularly applicable to the silicone rubber surface.
The fluororubber is a synthetic rubber with the molecular structure thereof containing fluorine atoms. There are many species and usually it is signified by the number of fluorine atoms of fluorine-contained units in the copolymer. Such as: fluororubber 23 is a copolymer of vinylidene fluoride and chlorotrifluoroethylene; fluororubber 246 is a copolymer of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene etc. The molecular structure of fluororubber 23 is:

The fluororubber has excellent heat resistance, oil resistance and chemical resistance, and other features such as cold and steam resistance vary depending on the structure. In addition to military use, it has widely used in such fields as aerospace, automobile, industrial oil, petrochemical, industrial pollution control etc. The fluororubber is mainly used to fabricate such sealers as gasket, seal ring with heat resistance, oil resistance, chemical erosion resistance, and also used to produce hoses, impregnated products and protective equipment etc. For example, a fluororubber and preparation method thereof disclosed in CN201310421869. 9 uses the fluororubber coating as main material, thereby increasing the adhesion of the resulting coating to the metal. The formulation of disclosed material contains 100 parts of fluororubber, 30 to 60 parts of carbon black, 3 parts of magnesium oxide (MgO), 6 parts of calcium hydroxide (CaOH), 1 to 5 parts of vulcanizing agent, 10 to 100 parts of silicone resin, 250 parts of organic solvent, 1 part of defoamer, 0.5 parts of leveling agent. But this coating cannot be particularly applicable to the fluororubber surface.
Since the various performance requirements for silicone rubber or fluororubber products in each field, coating is often coated on the surface of base material to promote the aesthetic appearance and some other special performance of the silicone rubber or fluororubber products, and in view of the special chemical structure of the base material, it has a poor mechanical performance, a strong inertia, a low surface energy, and general coating cannot attach thereon at all while some individual coatings can attach thereon only by corona or flame treatment of the silicone rubber or fluororubber base material. Even so, the coating still has a poor attachment onto the silicone rubber or fluororubber surface. The requirement for long-time use cannot be met. Those materials with low surface energy similar to the silicone rubber or fluororubber are more difficult to be attached by other present coatings.